Toner, image forming apparatus, image forming method and process cartridge

Abstract

An electrostatic image developing toner including toner core particles each containing at least a first resin and a colorant, and fine resin particles formed of a second resin, wherein part of each of the fine resin particles is embedded in each of the toner core particles, and the remaining part of the fine resin particle is exposed on a surface of the toner core particle to form a protrusion, and wherein when a rate of the part of the fine resin particle to the fine resin particle is indicated by an embedment rate, an average of the embedment rates in the fine resin particles is 40% to 80%.

What is claimed is: 
     
       1. An electrostatic image developing toner comprising:
 toner core particles each containing at least a first resin and a colorant, and 
 fine resin particles formed of a second resin, 
 wherein part of each of the fine resin particles is embedded in each of the toner core particles, and the remaining part of the fine resin particle is exposed on a surface of the toner core particle to form a protrusion, and 
 wherein when a rate of the part of the fine resin particle to the fine resin particle is indicated by an embedment rate, an average of the embedment rates in the fine resin particles is 40% to 80%, wherein a standard deviation of the embedment rates is 10 or less. 
 
     
     
       2. The electrostatic image developing toner according to  claim 1 , wherein the fine resin particles have an average sphericity of 0.90 or more. 
     
     
       3. The electrostatic image developing toner according to  claim 1 , wherein an amount of the fine resin particles is 1% by mass to 20% by mass relative to the electrostatic image developing toner. 
     
     
       4. The electrostatic image developing toner according to  claim 1 , wherein the first resin is a polyester resin. 
     
     
       5. The electrostatic image developing toner according to  claim 1 , wherein the first resin has an acid value of 2 mgKOH/g to 25 mgKOH/g. 
     
     
       6. The electrostatic image developing toner according to  claim 1 , wherein the second resin is a vinyl resin. 
     
     
       7. The electrostatic image developing toner according to  claim 1 , wherein an amount of a styrene monomer among monomers forming the second resin is 80% by mass to 100% by mass. 
     
     
       8. The electrostatic image developing toner according to  claim 1 , wherein an amount of an acid monomer among the monomers forming the second resin is 0% by mass. 
     
     
       9. The electrostatic image developing toner according to  claim 1 , wherein the first resin has a glass transition temperature Tg1 which satisfies expression (1) below:
   45° C.≦Tg1≦70° C.  (1)
 
 
     
     
       10. The electrostatic image developing toner according to  claim 1 , wherein the second resin has a glass transition temperature Tg2 which satisfies expression (2) below:
   45° C.≦Tg2≦100° C.  (2)
 
 
     
     
       11. The electrostatic image developing toner according to  claim 1 , wherein the toner core particles each further contain a modified polyester resin containing a urethane group, a urea group or both of the groups. 
     
     
       12. The electrostatic image developing toner according to  claim 1 , wherein the toner core particles each further contain a releasing agent. 
     
     
       13. The electrostatic image developing toner according to  claim 1 , wherein the electrostatic image developing toner further contains as an additive fine silica particles whose surfaces have been hydrophobized. 
     
     
       14. The electrostatic image developing toner according to  claim 1 , wherein the electrostatic image developing toner is obtained through a process including producing the toner core particles, and attaching and fusing the fine resin particles on the surfaces of the toner core particles. 
     
     
       15. The electrostatic image developing toner according to  claim 14 , wherein the toner core particles are obtained through granulation performed by emulsifying or dispersing, in an aqueous medium, an oil phase containing at least the colorant and the first resin, a precursor of the first resin, or both of the first resin and the precursor. 
     
     
       16. The electrostatic image developing toner according to  claim 15 , wherein the electrostatic image developing toner is obtained by adding an aqueous dispersion liquid of the fine resin particles to the aqueous medium containing the toner core particles emulsified or dispersed therein, to attach and fuse the fine resin particles to the surfaces of the toner core particles. 
     
     
       17. A toner container comprising:
 an electrostatic image developing toner, and 
 a container, which houses the electrostatic image developing toner, 
 wherein the electrostatic image developing toner comprises toner core particles each containing at least a first resin and a colorant, and fine resin particles formed of a second resin, 
 wherein part of each of the fine resin particles is embedded in each of the toner core particles, and the remaining part of the fine resin particle is exposed on a surface of the toner core particle to form a protrusion, and 
 wherein when a rate of the part of the fine resin particle to the fine resin particle is indicated by an embedment rate, an average of the embedment rates in the fine resin particles is 40% to 80%, wherein a standard deviation of the embedment rates is 10 or less. 
 
     
     
       18. A developer comprising:
 an electrostatic image developing toner which comprises toner core particles each containing at least a first resin and a colorant, and fine resin particles formed of a second resin, 
 wherein part of each of the fine resin particles is embedded in each of the toner core particles, and the remaining part of the fine resin particle is exposed on a surface of the toner core particle to form a protrusion, and 
 wherein when a rate of the part of the fine resin particle to the fine resin particle is indicated by an embedment rate, an average of the embedment rates in the fine resin particles is 40% to 80%, wherein a standard deviation of the embedment rates is 10 or less.